Grip-tread for elastic tires.



G. L. HOFF.

GRIP TREAD FOR ELASTIC TIRES.

APPLICATION mum mums. 1010.

1,035,586. Patented'Aug'. 13, 1912.

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'CARLTON L. HOFF, OF YORK, IENJS'faYLVANIA.

GRIP-TREAD FOR ELASTIC TIRES.

Specification of Letters Pateiit. Patented Aug. 13,1912- Application filed time 15, 1910. Serial no. 567,085.

To all whomit may concern Be it known that I. Canurox l Hort, a

' citizen of the United States, residing at scription of the same reference being bad tion. Fig. 2 is an elevation from to the accompanying drawings, forming a part of thisspecitication, and to the figures and letters of reference marked thereon.

This invention relates to certain improvements in grip treads for tires, the invention being more especially applicable to structures designed for use in connection with inflated tires or tires having. an elastic tread surface substantially convex in cross-section.

Objects of the invention are to provide a grip tread of the readily detachable type but having practically continuous gripping members extending around the wheel on each side of the center or plane of greatest diameter of the wheel and to prevent lateral displacement of such gripping members by transverseconnections, preferably of such character as will subject the center portion of the tire tread to the least possible wear, suitable means being" provided to retain the grip members on the wheel.

Other objects of the invention are to provide a convenient and simple means for put ting the grip members under the desired ten-- sion and for securing them in position.

In the accompanying drawings-Figure l is a side elevation of a wheel equipped with a grip tread embodying the present invena point of view in the plane of the wheel. Fig. 3 is a section through the topof a tire equipped with a grip embodying the present improvements. Fig. 4 is a section through the bottom of a loaded tire e'quipped with a grip tread embodying the present improvements.

Similar letters of referencein the several figures indicate the same parts. r

The grip tread of the present invention embodies parallel grip members, preferably twisted chains A. spaced apart a distance which will cause them to occupy positions at opposite edges of the tread surface of the tire and in position to contact with the surface of the roadway between the edges ofthe tread surface of the tire and roadway. The

longitudinally extending grip members or chains are "held in proper spaced position with relation to each other and to the tire bv cross-connections which are preferably relatively insignificant as grip members and are conveniently in the form of long links B round in cross-section to avoid wear on the tire and having eyes I) at. the ends which en gage the proximate bars of the respective chains. The length of the links should be such that the chains will be positioned as before indicated on opposite sides of the effective tread surface of the tire but. still sufficiently near the center to lie under the edges of the tread surface when said surface is in contact with the roadway and slightly flattened by contact with the roadway.

The position of the grip members will be best appreciated by an inspection of Figs. 3 and t in which it will be seen that the grip members are in the best position to prevent any side slip or skidding of the wheel and are also in effective position to increase the traction of the wheel. They .form in ellt'ect continuou gripping surfaces between the tire tread surface and roadway which will effectually prevent a skid from commencing, thus overcoming one of the chief defects in the type of tread grip employing transverse f rllpplllg members between which relatively longtire surfaces contact with the roadway with no grip member in effective position to prevent the skid from starting. Any suitable means may beemployed to prevent the escape of the grip members from the wheel such, for instance, as short sectional side chains D and jointed links 1. One of these sectional side chains may conveniently be employed as the means for taking-up or tensioning the grip members. For this purpose one end of each grip member is provided with a ring E through which the op osite end is passed and drawn back by an a justin or take-up device, such as the strap F forming a partof the sectional side chain.

The transverse connecting members B may be conveniently made to conform to the transverse contour of the tire where it contacts with the roadway and as this will elevate the central part of the connecting members above the planeof the chains or grip members the whole device will be firmly retained even without the employment of side chains but the latter are desirable to give an increased factor of safety in resisting excessive strains.

-Wherethe longitudinal grip members re formed of twisted chain, as shown, it-j"i's --desirable, that links or meniber's should' engage the chain links at the higher points so that the eyes of the 'connecting members are not 'pressed' into the tire andfor this reason thechain's should be of right-and leiftitwist respectively and-the grip should be "applied-tothe wheeliii such manner'that the traction tends to 'move'th'e connecting members to the higherends of" 10. the. side bars of the-links aswill be readily understood. Y 4

ip of the construc- It: is desirablejwith a tionset forth-to have t e' grip members tit tightly about the tire so as topre'vent as 5 far as practicable lateral play fi or movelinent, thus there will belittle creeping of Y the grip and the chains will pass down under the'edges of the tire .tr'ead surface in effective position to prevent skidding but 2 without subjecting the center of the tire tread to appreciable increased 1 wear.

In other words, the wear on the tire from use .of the grip members occurs on those porvtions of .the tire least-subject to "wear in the normal use of the tire and has the effect of distributing the wear. over a larger area Having thus described my invention, what I claimas new-and desire to secure by Let- 0 ters Patent of the United States. is-

1. A removable tread grip embodying parallel'independently flexible chains spaced apart with a clear space for the admission of the tread of the tire between them, and substantially rigid transverse connections loosely connected at' opposite ends with the chains tohold the chains at opposite edges of the tread surface of the tire in'position to be constantly pinched between the sides of the tire and roadway, whereby the invented at all points around the circumference of the tire-and the wear between 'the chains and tire is confined to portions of the tread subjected to the least wear by contact 1 parallel chain face of the .tire project thegroundand occupying positions at op.

auguration of any skidding action is pre- I j ma s s with the roadway, said grip embodying means whereby it is removably held in po* sition.

tread grip embodying .cont-inuous between them through vts hich the tread surinto contact with posite edges of the treadsurface whereby theedges' of thejtire tread sur'f ceare supported by the-gripmembe-rs r-igi transverse links jointed to the chains for holding them in spaced' relation, a ring on one end of each grip member and through which the opposite end of the memberpasses, side chaihs connected ateach end and at a p'ointintermediate the ends with the grip for holdlng the grip in position on the wheel one of said side chains being connected at one endgrip members "having ,a space to the end of the grip member paming I through the ring, and an adjusting means forming part of said lastmentioned side chain.

3. A tread grip embodying parallel chain I holding the grip members in spaced relation,,sa1d ,links having eyes engaging the higher side of opposite links of the grip members whereby theeyes of the links will be supported away from the tire} means for adjusting the length of thegripmembers, and means for'holding the grip in place embodying sectional side chains. I

CARLTON L. HOFF.

\Vit'nesses E; PHIIJP S rAnz, ANDREW J Hrm 

